drasys.or.stat.model
Class QuadraticMatrix

java.lang.Object
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  +--drasys.or.matrix.RealContainer
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        +--drasys.or.matrix.Matrix
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              +--drasys.or.matrix.FunctionMatrix
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                    +--drasys.or.stat.model.QuadraticMatrix

public class QuadraticMatrix

extends FunctionMatrix

Adds virtual columns to a matrix for quadratic modeling. The new array contains the original columns followed by all pair-wise product terms. The method 'getProductIndex' can be used to find the index of the product terms from the original column indices. If the original matrix has 'n' columns then the quadratic matrix will have 'n+n^2' columns and be defined as:

Q[i][0,...,n-1] = M[i][0,...,n-1] (Original variables)
Q[i][n + j*n + k] = M[i][j]*M[i][k] (Products)

References:

Applied Linear Statistical Models (Irwin Series in Statistics)
    Michael H. Kutner, et al / Hardcover / Published 1996
Numerical Recipes in C : The Art of Scientific Computing
    William H. Press, et al / Hardcover / Published 1993

See Also:

Serialized Form

Fields inherited from class drasys.or.matrix.FunctionMatrix

_sizeOfColumns, _sizeOfRows

 

Fields inherited from class drasys.or.matrix.RealContainer

_epsilon, _globalEpsilon

 

Constructor Summary

QuadraticMatrix(MatrixI matrix)           Add columns to matrix to create a new matrix containing the original variables plus the quadratic variables.

 

Method Summary
double	functionElementAt(int row, int column)           Computes the values for the additional columns.
int	getProductIndex(int column1, int column2)           Return the index of the column in the quadratic matrix for the product term for column-1 and column-2.

 

Methods inherited from class drasys.or.matrix.FunctionMatrix

elementAt, isColumnMajor, isNull, isRowMajor, setElementAt, setElements, sizeOfColumns, sizeOfElements, sizeOfRows

 

Methods inherited from class drasys.or.matrix.Matrix

columnElements, elements, equals, equals, getArray, rowElements, setColumn, setDiagonal, setElements, setRow, sum, sum, sum, sumOfSquaredDifferences, sumOfSquaredDifferences, sumOfSquaredDifferences, sumOfSquares, sumOfSquares, sumOfSquares, toString

 

Methods inherited from class drasys.or.matrix.RealContainer

equals, getEpsilon, getGlobalEpsilon, setEpsilon, setGlobalEpsilon

 

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

 

Constructor Detail

QuadraticMatrix

public QuadraticMatrix(MatrixI matrix)

Add columns to matrix to create a new matrix containing the original variables plus the quadratic variables.

getProductIndex

public int getProductIndex(int column1,
                           int column2)

Return the index of the column in the quadratic matrix for the product term for column-1 and column-2.

functionElementAt

public double functionElementAt(int row,
                                int column)

Computes the values for the additional columns.

Overrides:

functionElementAt in class FunctionMatrix